1. Field of the Invention
The present invention relates to an air conditioner and, more particularly, to an air conditioner adapted to air-condition a room or a passenger compartment of a vehicle.
2. Description of the Related Art
In a known air conditioner of this kind such as disclosed in Japanese Patent Laid-Open No. 229713/1989, the temperature sensation of the passenger in a vehicle is estimated only from the present temperature of the skin of the passenger, and then the passenger compartment is air-conditioned according to the estimated temperature sensation.
In this known air conditioner, it is assumed that the temperature of the skin of the passenger has a linear relation to the temperature sensation. The temperature of the skin is linearly transformed to estimate the temperature sensation of the passenger. Therefore, if the temperature of the skin that is information about the temperature sensation lies in a region where a linear relationship is held between the temperature of the skin and the temperature sensation, then no problems take place. However, if the temperature is outside this region as encountered when the sun suddenly becomes fiercer or lesser, i.e., the ambient condition changes suddenly, then the temperature sensation actually felt by the passenger fails to correspond to the estimated temperature sensation. As a result, the passenger compartment is inadequately air-conditioned. If a more violent temperature change occurs, then the effects of this violent change may linger on the temperature sensation. In the prior art techniques, the temperature sensation is estimated, taking account of only the present skin temperature. Consequently, the lingering effects or aftereffect cannot be taken into consideration.